Classification of Intact Cereal Flours by Front-Face Synchronous Fluorescence Spectroscopy

Synchronous fluorescence spectroscopy, a technique that measures both the absorption and the emission properties of a sample in a single measurement, was used for the analysis and classification of intact cereal flours (wheat, corn, rye, buckwheat, rice, and barley). Total synchronous fluorescence spectra recorded in constant wavelength mode show clear differences in the emission spectra of different flours due to variances in intrinsic fluorophore concentrations and their microenvironments. Principal component analysis, cluster analysis, and partial least squares discriminant analysis are used to assess the ability of synchronous fluorescence measurements to differentiate and classify intact samples of different flour types. The flour specimens were obtained directly from a market in Belgrade and had different expiration dates to provide a more representative set of samples. The results of the current analysis suggest that chemometric methods applied on synchronous fluorescence data can discriminate and classify flour types and that the best results are achieved using a combination of synchronous fluorescence measurements at synchronous intervals of 7 and 20 nm. The quality of results, the high speed of measurements, and the avoidance of extensive sample preparation make synchronous fluorescence spectroscopy a promising technique for cereal research.